Grinding of microporous coatings using impregnated grinding wheels

High chemical and adhesive activity of the nickel- and iron-based microporous coatings in contact with abrasive grinding wheels helps to fasten contacting bodies and to maximize adherence of the coating particles to the working surface of the cutting tool. These phenomena increase heat and power intensity of the process that in turn causes the increasing wheel wear, surface roughness as well as structural and phase transformations in surface layers of some parts. Consequently, one of the primary targets in order to improve the grinding efficiency is to reduce the temperature, on the one hand, and to reduce the useless energy consumption, on the other hand. The adhesive and chemical activity of microporous coatings with respect to abrasive grains can be reduced by finding ways reducing the surface energy of the contacting pair. The central idea in the theory of physical-chemical mechanics of materials is a concept to facilitate the deformation of bodies in the medium with surface-activated substances. These substances embrittle metal and accelerate its deformation through adsorption and electrocapillary effects. The paper proposes a method to improve the efficiency of grinding the microporous coatings by reducing the interaction between the contacting pairs through the introduction of special compounds in the cutting area, which in contact with juvenile surfaces of the material being processed form protective films on the material and thus prevent direct contact of the coating with wheel grains. New compounds of liquid impregnators are tested when grinding the microporous coatings using a flat surface grinder and a plunge-cut grinding method without lubricating-cooling fluids. Water soluble polymers and aqueous solutions of amines, fatty acids and carbamides are used as impregnators for wheels. The paper provides the results of comprehensive studies of the cutting power of electrocorundum wheels with ceramic bond impregnated with different compounds compared with non-impregnated wheels. The influence of impregnators on core parameters of the grinding process such as resistance and wear of an abrasive tool, energy consumption and roughness of a ground surface are studied. The studies revealed that when grinding the microporous coatings under given conditions the electrocorundum impregnated wheels have higher cutting power as compared with non-impregnated wheels. Comprehensive analysis of the studies based on a rating method revealed that when using the flat grinding method for the nickel- and iron-based microporous coatings the highest cutting power is attributed to wheels impregnated by triethanolamine and oleic acid impregnators.

microporous coatings, abrasive tool, grinding, impregnation, wheel resistance, cutting power, impregnator